The first picture of that knock"
This is the "knock" in your motor
This shows photographically what occurs
in the engine cylinder as carbon forms,
when regular gasoline is used. The increased
heat and pressure created by the carbon
cause the gasoline to explode too quickly,
with the result that there is an accumula
tion of high pressure heat waves which
strike against the cylinder walls so violently
as to produce an audible metallic sound.
The bumps in the line are that "knock."
This is how "ETHYL" knocks it out
And this shows photographically what goes
on in the same cylinder under the same con
ditions when regular gasoline is treated with
"ETHYL" fluid. Note the absence of"knock
bumps"; the evenness of the pressure changes.
The "ETHYL" fluid has neutralized the heat
ing qualities of the carbon deposits and by
maintaining the normal combustion rate of
gasoline has turned the increased pressure
due to carbon into increased power.
THESE PHOTOGRAPHS were
made possible by a special in
strument invented by General
Motors Research Laboratories to
find out what goes on in an auto
mobile engine's cylinder when
"knocking" occurs.
That invention led to the discovery
that what you may call an "engine
knock" or a "spark knock" is in
reality a fuel knock. It is due to the
tendency of a regular gasoline to
explode too quickly as carbon forms
and increases temperature and com
pression (pressure).
Having determined the character
of "knocking,"
General Motors
developed "ETHYL" fluid, a pat
ented chemical compound which
when added in very small quantities
to regular gasoline forms Ethyl
Gasoline, the most effective "anti
knock" fuel yet known.
Ethyl Gasoline transforms carbon
deposits from a liability into anasset.
It produces more power on hills and
heavy roads. It gives a faster "pick
up," reduces gear-shifting, lessens
vibration and engine wear and tear;
and saves the trouble and expense
of carbon removal.
Ethyl Gasoline has increased the
motoring satisfaction of hundreds of
thousands of car drivers. It is des
tined to play a still more important
part in the automobile history of
the future. TRY IT.
ETHYL GASOLINE CORPORATION
25 Broadway, New York
ETHYL GASOLINE is now gen
erally available throughout the
United States and Canadathrough
the following oil companies,
licensed to mix "ETHYL" fluid
with gasoline. The "ETHYL"
trademark on the pump is your
protection.
Associated Oil Company ' Atlantic
Refining Co. I Beacon Oil Com
pany " Continental Oil Company m
Humble Oil & Refining Co. ' Im
perial Oil Limited (Canada) I
Pennzoil Company I Refiners Oil
Company I Spears & Riddle Co. "
Spokane Oil & Refining Co.
StandardOil Company (Indiana) "
StandardOil Company(Kentucky)
SStandard Oil Company of Louis
iana " Standard Oil Co. (Neb.) I
Standard Oil Company (N. J.)
Sterling Oil Company r Union
Oil Company of California
Walburn Petroleum Co. Waverly
Oil Works
ETHYL GASOLINE